mine

No visible egg; it is deposited below the upper epidermis, generally close to a major vein. From there begins a short, quickly widening corridor that contains much frass, especially in its first part. The corridor opens into a large, very transparant, almost full depth blotch that often overruns the initial corridor. Frass in loose grains, larger as the larva increases in size. The frass is dry, and in old mines it may accumulate like pepper grains in the lowest part. Larva solitary, belly-up in the mine; firsst abdominal segment ventrally with a brown or black spot, like also in thorax 2 and 3. Prepupa totally white.